No idea, I only played F3 a very long time ago, and the very beginning / intro of NV. But I feel that would only prove my point further because they clearly did not get surprised by a foreign launch if they were already in the vault but already preparing for it, which would be hard to do since they likely did not have knowledge of a possible Chinese launch long in advance. The whole cold war state of getting nuked was going on for quite a long time in that universe so that feeling was already there anyway. I don’t think they strictly stated that they nuke themselves either, Vault-Tec might’ve just attacked China with them, which then retaliated due to MAD and became the scapegoat.